If the latter, what's to stop someone from taking those files, getting their own clearance, and submitting them to PG as their own work?
What's to stop a PM and Content Provider who is sick to death of having their hard work stuck in limbo year after year at DP from taking a SR copy, cleaning it up and submitting it to PG -- given that they are the holder of the CC in the first place and the person who did the lion's share of the work cleaning it up for submission to DP in the first place? Answer: Simple Integrity, and the desire to play fair with DP even when DP is not playing fair with that PM and Content Provider. What is NOT fair IMHO is when works that volunteers have put their blood sweat and tears into gets stuck forever at DP while apparently a commercial entity has taken the SR from DP and is selling it on Amazon. Work that volunteers put into the public domain should go there first, and THEN back to the commercial providers. But, this is what happens when you take years sitting on books instead of allowing them to be finished.